1. Field of the Invention
The present invention relates generally to an antenna, and more particularly to a multi-band antenna used in a portable electronic device.
2. Description of the Prior Art
With the development of wireless communication, more and more portable electronic devices, such as a notebook, install an antenna system for working in a Wireless Local-area Network (WLAN). Transmitting and receiving signals plays an important role in wireless communication process. In recent years, a majority of WLAN bases on Bluetooth technical standard or 802.11 technical standard. Antenna in Bluetooth technical standard is based on 2.4 GHz frequency band, and in 802.11 technical standard is based on 2.4 GHz and 5 GHz. So, antenna in notebook mostly works at the above frequency bands at the present time.
However, more and more people dissatisfy their electronic devices only working in an immovable network (signal transmission distance is 10 meters in Bluetooth which almost doesn't permit the electronic devices to move.) or a only short-haul movable network (signal transmission distance is 150 meters of 802.11 technical standard which limits the move of the electronic device except between work rooms.) of the WLAN. Making the portable electronic devices working in WWAN (Wireless Wide Area) or GPS (Global Positioning System) is a purpose of the many people. Because the portable electronic devices can work or amuse in broaden range in WWAN or GPS. In recent years, WWAN adopts two technical standards of GSM and CDMA. Operating frequency bands of the GSM and CDMA are 900/1800 MHz, and operating frequency band of the GPS is 1.575 GHz. So, an antenna of a notebook must operate in above frequency bands, the portable electronic device is capable of working in WWAN and GPS. At present, the antenna used in the notebook only can work in one of technology standards of the WLAN, WWAN, and GPS. The antenna can't work in above three technology standards at the same time unless install three sets of antennas respectively work in above technology standards in the notebook. However, this is difficult to install three sets antennas in the limited inner space of the notebook and the antennas may influence one another when working. In addition, installing three sets of antennas also increase the cost of the notebook compared with installing one set antenna.
Hence, in this art, a multi-band antenna to overcome the above-mentioned disadvantages of the prior art will be described in detail in the following embodiment.